The Curious Case of Benjamin Button is easily director David Fincher’s most ambitious project to date, but it’s also his most tonally uneven and least satisfying. Although his features have been based on others’ screenplays, he’s always brought a fantastically realized sense of self and style to each of his films. The grimy vomit-noir of Seven and the minor masterpiece that was Zodiac differ in texture and sensibility, but they’re alike in their devotion to a unifying aura within their respective universes; basically, Fincher makes movies that feel complete. But The Curious Case of Benjamin Button, though filled with promised and sprinkled with moments of genuine power and connection, is ultimately too unsteady to serve as anything other than a sad reminder of the great film that lies somewhere beneath the surface.

The film opens in a New Orleans hospital room as the rain of the approaching Hurricane Katrina begins to hit the window. Daisy (Cate Blanchett) is old and dying, and she’s spending what will be her last hours alive with her daughter, Caroline (Julia Ormond). Daisy tells Caroline the story of the giant clock that used to be at the train station, a clock that ran backward, and her recollection is illustrated in the jerky, cracked style of an old film reel: It’s the first indication that Fincher isn’t just trying for something grand but for an intentionally cinematic feeling, an air of presentation that references the story’s own twists even as they unfold. But when Caroline begins to read to her mother from a battered old diary, the flashbacks take on the same polished look of the present-day scenes, and the narration shifts to the voice of Benjamin Button (Brad Pitt), who takes over from there. It’s Benjamin who tells the story of his own life, tracing the events of his unique look at coming of age. The gimmick of the film — written by Eric Roth and based on the short story by F. Scott Fitzgerald — is that Benjamin ages in reverse: Born around 1918, as an infant he looked like an old man, and as time passes, his body grows in stature and gradually becomes less gnarled and decrepit until he turns into a better-than-average-looking guy. After Benjamin’s mother dies giving birth, his horrified father leaves the wrinkled newborn on the back steps of an old folks home, where he’s adopted and raised by one of the workers, Queenie (Taraji P. Henson).

Fincher achieves the effect through a mix of makeup and CGI whose combined outcome walks the gray area between magical and unsettling. It’s Pitt’s animated face slapped on the body of someone else to make him appear to be a withered old man, as well as a modulated version of his voice. As a result, it’s impossible to relate to the character as anything other than kind-of-Pitt until he ages to the point that he can be portrayed by the actor in makeup. The early scenes in the home are also where Fincher stumbles a bit and the film slides from a drama with comic relief to a film that doesn’t quite know what tone to take. There’s the old man who talks about being struck by lightning seven times, each recollection punctuated by a brief flashback, constructed like that same old film reel, of the man being blasted from on high; these scenes are often jammed haphazardly between those dealing with Benjamin’s growing understanding of the nature of life, death, and the world around him, but it’s never clear if Fincher is trying to lighten a dark moment, darken a light one, or if he just didn’t know what to do.

But the center of the film is where the wheels begin to click and Fincher begins to tell part of a genuinely tragic love story. As a young/old man, Benjamin meets Daisy, whose grandmother lives in the home, and the two take to each other instantly. The bulk of the film, and its best moments, deal with their close friendship as it skips across time like a stone on water, with Benjamin growing younger as Daisy turns from girl to woman. Benjamin sets off to see the world when he’s 17 and looks like he’s 65, promising to write the teenage Daisy, and Fincher spends most of the lengthy second act following Benjamin’s travels and service in World War II — the tugboat he worked was pressed into service following Pearl Harbor — and Daisy’s young adulthood as she moves to New York to become a dancer. Their sporadic reunion scenes are never less than heartbreaking, too: They long ago realized they love each other more than they can admit or define, but, as is pretty much always the case, they can never connect on the timing. It’s in these reflections of doomed but compelling love, as Benjamin looks younger and Daisy looks older, that Fincher’s film finds its heart, even if only for a while. But after a certain point, the story begins to sag under the weight of its framing device, cutting back to the hospital room as Daisy and Caroline deal with the effects of the tale that’s being told. These returns to the present turn Benjamin’s story from a sprawling one into one that’s been chopped and reassembled, and they negatively transform the film from one man’s story to something more jumbled and less attainable. Had Fincher and Roth eliminated the present-day framing and relied on the strength of the core story, the film would have been tighter, truer, and more resonant.

Despite a few moments of (maybe not totally unintentional) eeriness involving the extreme ends of Benjamin’s life, the makeup and CGI are more nuanced and impressive than any other live-action feature to date. From a technical standpoint, it’s understandable that Fincher didn’t want the camera to dwell too long on Pitt’s or Blanchett’s faces when they’d been digitally buffed to a youthful sheen, but he and cinematographer Claudio Miranda make it work to their advantage by filling the film with shadows; it’s no accident that every major turning point or revelation happens when one character is cloaked in the dimness of an empty room, speaking to someone in the light of the living world. Pitt and Blanchett do wonderful work carrying a script that often seems reluctant to give them a chance to do any good together for more than a few minutes. Roth’s screenplay, despite its scope, seems to occasionally borrow too heavily from his work on Forrest Gump, from the Southern setting to the years-long love affair that just barely works to the preponderance of death, etc.

“We are not little children any more,” Daisy admonishes Benjamin when she’s getting older and he’s still a little old. It’s a fantastic line not just because it plays into the film’s key theme of loss and the transitive nature of love but because it’s a tacit acknowledgement of just how weird Benjamin’s situation is, and that Daisy knew from the start that he was a boy in an elderly body and that he’s aging inside even as his body grows younger. The simple acceptance of that fantastical way of life is sorely underplayed in the film, and though the story’s time frame allows Benjamin to live pretty easily off the grid, it would have been nice for Fincher to have dug deeper into the lives and reactions of Benjamin’s friends and loved ones as they watched him slide backward through life. But like too many other parts of the story, it just doesn’t connect. That’s the main problem with the film: Like its central characters, Fincher and the story come at each other crosswise, meeting in the middle but ultimately consigned to pass unfulfilled, knowing what might have been but unable to change what is.

Daniel Carlson is the managing editor of Pajiba and a low-level employee at a Hollywood industry magazine. You can visit his blog, Slowly Going Bald.